Fuel filling device and fuel leakage detection method

ABSTRACT

A fuel filling device is provided with a fuel supply adjusting section which adjusts the amount of fuel supplied, a fuel feed line which feeds fuel from a fuel supply adjusting section to a vehicle W, a nozzle removably coupled to vehicle W that supplies fuel from fuel feed line to vehicle W, and a discharge device that discharges fuel present within fuel feed line to the outside to prevent deterioration of packings used in the device in the case of filling a fuel at high pressure, while also facilitate the operation of a filling nozzle.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a fuel filling device that fillshydrogen or compressed natural gas as fuel into a vehicle, and to amethod of detecting fuel leakage of a fuel filling device.

[0003] 2. Description of Related Art

[0004] Development is proceeding on hydrogen automobiles and compressednatural gas automobiles using hydrogen gas and compressed natural gasfor fuel as next-generation automobiles. These automobiles arecharacterized by low emission levels of carbon dioxide gas, NOx, SOx,and other pollutants.

[0005] When refueling these automobiles, the automobiles are driven to arefueling station provided with a fuel filling device (dispenser) thatfills the hydrogen gas or compressed natural gas used as fuel, and fuelis then replenished at that refueling station in the same manner ascurrent gasoline-fueled automobiles.

[0006] Studies are being conducted on the safety and other aspects ofthese automobiles and fuel filling devices (refer to, for example, JapanGas Association, “Safety and Technical Guidelines for Compressed NaturalGas Stations”, April 1998, p. 44).

[0007] In the case of using compressed natural gas as fuel, undergroundsupply pipes that supply compressed natural gas to homes andcorporations are used in fuel filling devices. Compressed natural gasthat has been supplied through a pipe that branches from a supply pipeused to feed compressed natural gas to homes and corporations is boostedin pressure with a compressor, and this compressed natural gas is thensupplied to a plurality of storage tanks at respectively differentfilling pressures followed by maintenance and management of that supply.

[0008] In the case of filling compressed natural gas into the fuel tankof an automobile, compressed natural gas is begun to be supplied byremoving compressed natural gas from one of the plurality of storagetanks at a low filling pressure, and then the pressure of the automobilefuel tank approaches the pressure of the storage tank, the supply pathswitches to another storage tank having a higher filling pressure thanthis storage tank.

[0009] In this manner, by supplying compressed natural gas from a tankwhile sequentially switching to a storage tank filled at a higherfilling pressure, filling is carried out so as not to cause rapidfilling accompanying sudden changes in pressure.

[0010] The maximum filling pressure of storage tanks in conventionalcompressed natural gas fuel filling equipment is about 25 MPa.

[0011] In the case of using hydrogen gas for fuel, a method in whichhydrogen gas is generated by primarily reacting natural gas and water ata high temperature of 700-800° C., and a method in which hydrogen gas isgenerated by electrolysis of water, are being considered.

[0012] The hydrogen gas generated with these methods is boosted inpressure by a diaphragm-type pressure booster, and then filled into aplurality of storage tanks at respectively different pressures followedby maintenance and management of that supply.

[0013] During filling of fuel, similar to the case of compressed naturalgas, filling is carried out by removing fuel while sequentiallyswitching the plurality of fuel tanks among low pressure, intermediatepressure and high pressure tanks so as to prevent the occurrence ofrapid filling.

[0014] The maximum pressure of hydrogen gas fuel storage tanks incurrent prototype equipment is about 40 MPa.

[0015]FIG. 5 shows an example of a fuel filling device that fillshydrogen gas or compressed natural gas into the fuel tank of anautomobile.

[0016] This fuel filling device 50 is provided with a fuel supplyadjusting section 51 that adjusts the amount of fuel supplied, a fillinghose 61 coupled thereto that feeds fuel to a fuel tank T of anautomobile W, a nozzle 65 arranged on the end section of the fillinghose 61 that supplies fuel by being removably coupled to a line 73running to fuel tank T of automobile W, and a discharge hose 70, one endof which is coupled to nozzle 65, while the other end is open to theatmosphere via a valve 69 after passing through fuel supply adjustingsection 51.

[0017] A fuel distribution line 52 that sends fuel from a fuel source 60to filling hose 61 is provided in fuel supply adjusting section 51.

[0018] A mass flow meter 53, a flow rate adjusting valve 54, a cutoffvalve 55, and a pressure switch 56 are provided in fuel distributionline 52.

[0019] Fuel source 60 is composed of a plurality of storage tanks 60 k,60 m, and 60 n into which fuel has been filled at mutually differentpressures, namely a low pressure, an intermediate pressure and a highpressure, and these storage tanks 60 k, 60 m, and 60 n are switchablyconnected to fuel distribution line 52.

[0020] Nozzle 65 is a three-way valve, filling hose 61 is connected toconnection port 65 a of connection ports 65 a through 65 c, anddischarge hose 70 is connected to connection port 65 b. The remainingconnection port 65 c is located at a filling port 66, and filling port66 is able to be removably connected to a receptacle 71 serving as theconnection port of fuel tank T of automobile W in a single operation bymeans of a pipe coupling structure.

[0021] To prevent the fuel filling device from being damaged or the fuelfrom leaking when filling hose 61 and discharge hose 70 are subjected toa predetermined tensile force or greater due to automobile W mistakenlybeing driven away in the state in which filling hose 61 and dischargehose 70 are still connected, or due to being subjected to an externalimpact, an emergency release pipe coupling 62 is provided at anintermediate location of filling hose 61 and discharge hose 70 that isprovided with a cutoff function, which together with releasing whenacted on by a prescribed tensile force, prevents outside air fromentering the hose.

[0022] In fuel filling device 50, filling operation is performed withthe series of operations described below.

[0023] In the standby state, the connection port 65 a with filling hose61 of nozzle 65 of fuel filling device 50 is closed, and connection port65 c on the side of automobile W and connection port 65 b on the side ofdischarge hose 70 are connected.

[0024] When filling automobile W with fuel, nozzle 65 is connected sothat its filling port 66 engages with receptacle 71 of automobile W.

[0025] Next, after a handle 65 d of nozzle 65 is operated so as toconnect filling hose 61 and receptacle 71 of automobile W by connectingconnection port 65 a and connection port 65 c, fuel is filled from fuelsource 60 into fuel tank T of automobile W by pressing a filling startbutton (not shown) arranged on fuel supply adjusting section 51 of fuelfilling device 50.

[0026] Fuel is then filled into fuel tank T of automobile W throughfilling hose 61, nozzle connection ports 65 a and 65 c, and receptacle71 from fuel supply adjusting section 51.

[0027] During filling, the storage tank among storage tanks 60 k, 60 mand 60 n having a filling pressure which is higher than the pressure offuel tank T of automobile W at the start of filling while also being theclosest to the pressure of fuel tank T. At the same time, cutoff valve55 is opened and discharge valve 69 is closed.

[0028] Together with then suitably adjusting the opening of flow rateadjusting valve 54 by controlling the drive air supplied to flow rateadjusting valve 54 by a control section 68 based on the pressuredifference between the pressure of fuel distribution line 52 detected bypressure switch 56 and the storage tank pressure detected by pressureswitch 67, filling is carried out by sequentially increasing the fillingpressure in a stepwise manner so as to switch to the storage tank havingnext highest filling supply pressure when the pressure differencebetween the pressure of filling hose 61 and the pressure of the storagetank becomes smaller.

[0029] When the fuel is filled to a prescribed pressure value, and thevalue detected by pressure switch 56 reaches a prescribed pressure,pressure switch 56 emits a signal via control section 68 that causes alamp and so forth to light (not shown) to inform that filling iscompleted, while at the same time, cutoff valve 55 closes and dischargevalve 69 opens.

[0030] When filling is completed, the connection ports of nozzle 65 areswitched by handle 65 d. Namely, connection port 65 c and connectionport 65 b are made to be connected.

[0031] In this manner, when the connections ports of nozzle 65 areswitched by operating handle 65 d so that nozzle connection port 65 c onthe side of receptacle 71 and connection port 65 b leading to dischargehose 70 are made to be connected, fuel retained in line 73 runningbetween nozzle 65 and cutoff valve 74 of fuel tank T of automobile W isdischarged into the atmosphere via discharge hose 70.

[0032] Next, fuel filling operation is completed by disconnecting nozzle65 from receptacle 71.

[0033] Since nozzle 65 is a three-way valve, the direction in which theconnection ports are connected can be confirmed from the direction ofhandle 65 d.

[0034]FIG. 6 shows the changes in pressure of filling hose 61 anddischarge hose 70 during the filling operation process of this fuelfilling device 50.

[0035] During standby, the pressure of filling hose 61 maintains apressure equivalent to filling pressure PF of fuel tank T, and at thestart of filling, rapidly drops to the pressure of the coupled storagetank, increases to a desired pressure by sequentially switching to astorage tank of the next highest pressure, and then reaches a standbystate at a final filling pressure PF at completion of filling.

[0036] On the other hand, although the pressure inside discharge hose 70increases in order to discharge high-pressure fuel remaining atcompletion of filling to the atmosphere at the start of the standbyperiod, it is nearly at atmospheric pressure during the other steps.

[0037] In the case of a conventional fuel filling device 50, fuel fromthe previous refueling is retained in filling holes 61 when in a standbystate in which fuel is not being filled into automobile W.

[0038] Hydrogen is a gas that has the potential to explode in thepresence of an ignition source at a concentration of 4.0-75.0% in air.In addition, methane, which is the main component of compressed naturalgas, is a gas that has the potential to explode in the presence of anignition source at a concentration of 5.3-14.0% in air.

[0039] Consequently, it is not desirable to allow these gases to beretained within hoses and other lines.

[0040] At the current filling pressure at which fuel is filled into anautomobile fuel tank T, the distance capable of being traveled by theautomobile on a single refueling is about 200 km.

[0041] Although this traveling distance is determined by the capacity ofthe fuel tank T installed on the automobile W and its filling pressure,since there are limitations on the degree to which the capacity of fueltank T installed on automobile W can be increased, in order to extendthe traveling distance beyond 200 km, it is necessary to increase thepressure at which fuel is filled into fuel tank T, and higher fillingpressures are desired such as increasing filling pressure from thecurrent level of 40 MPa to 100 MPa.

[0042] However, in the case of filling device 50 of the prior art, whenthe filling pressure is increased, residual fuel remains at a highpressure within filling hose 61 or other lines during the standby state.

[0043] If fuel is allowed to be retained in the lines at this highpressure, fuel may permeate into the packings used in componentmachinery due to penetration, and this permeated fuel may causedeterioration of the packings as a result of swelling inside thepackings when pressure drops at the start of filling.

[0044] Since hydrogen gas in particularly is highly penetrable withrespect to the packings due to its small molecules, allowing hydrogen tobe retained in the lines was undesirable.

[0045] In addition, in the case fuel is allowed to be retained in thelines in a high pressure state, since the inside of nozzle 65 reaches ahigh pressure, the pressing force of the packing against the surfaceinside nozzle 65 that contacts the packing becomes higher, resulting inthe problem of it being difficult to open and close the valve of nozzle65, while also making it difficult to attach and release nozzle 65 toand from automobile W.

[0046] In view of the above problems, an object of the present inventionis to provide a fuel filling device capable of preventing deteriorationof packings of the device in the case of filling fuel at a highpressure, and capable of facilitating operation of a filling nozzle.

BRIEF SUMMARY OF THE INVENTION

[0047] A fuel filling device according to the present invention isprovided with a fuel supply adjusting section which adjusts the amountof fuel supplied, a fuel feed line which feeds fuel from the fuel supplyadjusting section to a vehicle, a nozzle removably coupled to thevehicle which supplies fuel from the fuel feed line to the vehicle, anda discharge device which discharges fuel within the fuel feed line tothe outside.

[0048] In the fuel filling device according to the present invention,preferably, the fuel supply adjusting section is provided with a fueldistribution line which guides the fuel to the fuel feed line, and thedischarge device is connected to the fuel distribution line.

[0049] A packing used for the fuel supply adjusting section, fuel feedline, or nozzle is preferably composed of one or two or more selectedfrom the group consisting of acrylonitrile butadiene rubber,hydrogenated acrylonitrile butadiene rubber, ethylene propylene rubber,fluorine rubber, polyacetal, and polyamide.

[0050] The packing used for the fuel supply adjusting section, fuel feedline, or nozzle is particularly preferably composed of one or two ormore selected from the group consisting of acrylonitrile butadienerubber, ethylene propylene rubber, and polyamide.

[0051] In the fuel filling device according to the present invention,preferably, the fuel feed line and fuel supply adjusting section arecoupled with an electrically conductive member, and the fuel supplyadjusting section is grounded.

[0052] In the fuel filling device according to the present invention,preferably, a flow meter which measures the flow rate of the fuel and aflow rate adjusting valve which adjusts the flow rate of the fuel areprovided in the fuel supply adjusting section, thereby enabling atheoretical filling volume, which is calculated based on the flow rateof the fuel calculated from the opening of the flow rate adjusting valveand the pressure difference between the upstream pressure and downstreampressure of the flow rate adjusting valve, to be compared with theactual filling volume detected with the flow meter.

[0053] A method of detecting fuel leakage of a fuel filling deviceaccording to the present invention comprises: a fuel filling devicebeing provided with a fuel supply adjusting section which adjusts theamount of fuel supplied, and the fuel supply adjusting section beingprovided with a flow meter which measures a flow rate of the fuel, and aflow rate adjusting valve which adjusts a flow rate of the fuel; whereinfuel leakage is detected by comparing a theoretical filling volumecalculated based on an opening of the flow rate adjusting valve and apressure difference between an upstream pressure and downstream pressureof the flow rate adjusting valve, and an actual filling volume detectedwith the flow meter.

[0054] Since the fuel filling device of the present invention isprovided with a discharge device that discharges fuel present in a fuelfeed line to the outside, fuel present in the fuel feed line and thelike can immediately be discharged after completion of fuel filling,allowing the fuel filling device to stand by in a state in which thepressure in the fuel feed line has decreased to nearly atmosphericpressure.

[0055] Consequently, the packings used in each of the compositeequipment that compose the fuel filling device can be prevented frombeing exposed to high-pressure fuel for a long period of time while inthe standby state, and permeation of fuel into the packings can beprevented in advance.

[0056] Accordingly, deterioration of packings caused by permeation offuel can be prevented, and fuel leakage and other accidents can beprevented.

[0057] In addition, since pressure inside a nozzle is at low pressure inthe standby state, operations such as connection and release of thenozzle can be facilitated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0058]FIG. 1 is a schematic block diagram of one embodiment of a fuelfilling device according to the present invention.

[0059]FIG. 2 is a partial cross-sectional view showing an emergencyrelease pipe coupling that can be used in the fuel filling device shownin FIG. 1 in the state in which it has been released.

[0060]FIG. 3 is a graph showing the changes in pressure in a fuel feedline during fuel filling of the fuel filling device shown in FIG. 1.

[0061]FIG. 4 is a schematic block diagram showing a coupled sectionbetween a fuel feed line and fuel distribution line in the fuel fillingdevice shown in FIG. 1.

[0062]FIG. 5 is a schematic block diagram showing an example of aconventional fuel filling device.

[0063]FIG. 6 is a graph showing the changes in pressure within a fillinghose and a discharge hose during filling of fuel of the fuel fillingdevice shown in FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

[0064] An embodiment of the fuel filling device according to the presentinvention is explained with reference to FIG. 1.

[0065]FIG. 1 is a schematic block diagram explaining one embodiment ofthe fuel filling device according to the present invention.

[0066] A fuel filling device 10 of the present embodiment is providedwith a fuel supply adjusting section 1 which adjusts the amount of fuelsupplied, a fuel feed line 11 which feeds fuel from fuel supplyadjusting section 1 to an automobile W, a nozzle 21 arranged on the endsection of the fuel feed line 11 which supplies fuel by being removablycoupled to automobile W, and a discharge device in the form of a fueldischarge line 9 which discharges fuel within fuel feed line 11 to theoutside.

[0067] A fuel distribution line 2 which feeds fuel from fuel source 60to fuel feed line 11 is provided in fuel supply adjusting section 1. Amass flow meter 3, a flow rate adjusting valve 4, a cutoff valve 5, anda pressure switch 6 are provided in fuel distribution line 2.

[0068] Fuel source 60 is provided with a plurality of storage tanks 60k, 60 m, and 60 n in which fuel is filled at mutually differentpressure, namely, a low, intermediate, and high pressure, respectively.Storage tanks 60 k, 60 m, and 60 n are switchably connected to fueldistribution line 2 by valves VK, VM, and VN.

[0069] A pressure switch 25 is provided in line 16 which connects fuelsource 60 and fuel distribution line 2.

[0070] Fuel discharge line 9 is provided with a cutoff valve 7 and acheck valve 8, one end of which is connected to fuel distribution line 2within fuel supply adjusting section 1, while the other end is open tothe atmosphere.

[0071] Nozzle 21 is able to be removably connected to receptacle(connecting section) 71 of automobile W in a filling port 22 on the endof nozzle 21.

[0072] A pipe coupling structure 72 is preferably employed for nozzle 21and receptacle 71 to block the entry of air when they are separated.

[0073] An emergency release pipe coupling 12 is provided in anintermediate section of fuel feed line 11.

[0074] Emergency release pipe coupling 12 is provided for preventingfuel filling device 1 from being damaged and fuel from leaking out whena predetermined tensile force or greater has acted on fuel feed line 11due to automobile W mistakenly being driven away in the state in whichfuel feed line 11 is still connected, or due to being subjected to anexternal impact.

[0075] As shown in FIG. 2, emergency release pipe coupling 12 isprovided with mutually removable upstream section 12 a and downstreamsection 12 b.

[0076] Upstream section 12 a is provided with a main body 15 a having afuel distributing part 13 a, and an upstream closing body 14 a whichcloses an opening 16 a of fuel distributing part 13 a.

[0077] Downstream section 12 b is provided with a main body 15 b havinga fuel distributing part 13 b, and a downstream closing body 14 b whichcloses an opening 16 b of fuel distributing part 13 b.

[0078] Closing bodies 14 a and 14 b are retractable, and are energizedin the direction in which they approach each other (forward direction)by springs 17 a and 17 b.

[0079] Main body 15 a of upstream section 12 a is provided with apushing section 19 a which causes closing body 14 b to move in theretracting direction, while main body 15 b of downstream section 12 b isprovided with a pushing section 19 b which causes closing body 14 a tomove in the retracting direction.

[0080] In emergency release pipe coupling 12, closing bodies 14 a and 14b are each moved in the retracting direction in the state in whichupstream section 12 a and downstream section 12 b are connected.

[0081] In the state in which closing bodies 14 a and 14 b have beenmoved in the retracting direction, openings 16 a and 16 b provided inmain bodies 15 a and 15 b are open, and fuel passes through fueldistributing sections 13 a and 13 b.

[0082] When fuel flows through fuel distributing sections 13 a and 13 bwhile in this connected state, fuel contacts packings provided inemergency release pipe coupling 12.

[0083] Examples of packings which have the possibility of contactingfuel are indicated with reference symbols 18 a through 18 m.

[0084] Preferable examples of packings used in fuel supply adjustingsection 1, fuel feed line 11, or nozzle 21 are composed of one or two ormore selected from the group consisting of acrylonitrile butadienerubber, hydrogenated acrylonitrile butadiene rubber, ethylene propylenerubber, fluorine rubber, polyacetal, and polyamide.

[0085] Particularly preferable examples of packings are composed of oneor two or more selected from the group consisting of acrylonitrilebutadiene rubber, ethylene propylene rubber, and polyamide.

[0086] These materials may applied to packings 18 a through 18 m ofemergency release pipe coupling 12. In addition, they may also be usedfor the packings used in nozzle 21. They may also be used for thepackings used in the parts composing fuel filling device 10 such as thepipe connections within fuel supply adjusting section 1.

[0087] The use of these materials makes it possible to preventdeterioration of the packings since it is difficult for fuel to permeateinto the packings even if these materials contact with fuel in a highpressure state. Consequently, the sealing of, for example, fuel feedline 11 and nozzle 21 is maintained, and fuel leakage can be preventedfor a long period of time.

[0088] Filling operation using fuel filling device 10 is explained asfollows.

[0089] When filling fuel into automobile W, filling port 22 of nozzle 21is connected to receptacle 71 of automobile W.

[0090] Next, together with flow rate adjusting valve 4 and cutoff valve5 provided in fuel distribution line 2 being opened, cutoff valve 7 offuel discharge line 9 is closed as a result of pressing a filling startbutton (not shown) installed in fuel supply adjusting section 1 of fuelfilling device 10.

[0091] As a result, fuel from storage tanks 60 k, 60 m, and 60 n entersautomobile W by passing through fuel distribution line 2 and fuel feedline 11, and is filled into fuel tank T through line 73.

[0092] During filling of fuel, fuel is preferably maintained at aconstant flow rate by suitably adjusting the opening of fuel flowadjusting valve 4 by controlling the drive air supplied to flow rateadjusting valve 4 by a control section 30 based on the pressuredifference between the pressure of fuel distribution line 2 detected bypressure switch 6, and the storage tank pressure detected by pressureswitch 25.

[0093] During filling of fuel, the storage tank among storage tanks 60k, 60 m, and 60 n is used which has a filling pressure that is higherthan the pressure of fuel tank T of automobile W at the start of fillingand which is also closest to fuel tank T.

[0094] When the pressure difference between the pressure of fuel feedline 11 detected by pressure switch 6 and the storage tank pressure ofpressure switch 25 becomes small, valve Vk, Vm, and Vn are switched toso as to switch to the storage tank having the next highest fillingpressure, and fuel is filled so that the filling pressure sequentiallybecomes higher in a stepwise manner.

[0095] When the fuel is filled into fuel tank T of automobile W to aprescribed pressure value, pressure switch 6 detects the prescribedpressure and emits a signal that causes a lamp and the like (not shown)to light in order to inform completion of filling. At the same time,cutoff valve 7 of fuel tank T of automobile W is closed.

[0096] In the case the pressure at which fuel is filled into fuel tank Tis to be a high pressure (e.g., 50-100 MPa), the inside of fueldistribution line 2 and fuel feed line 11 reaches a high pressure (e.g.,50-100 MPa) during filling of fuel.

[0097] Next, together with valves Vk, Vm, and Vn of each storage tank offuel source 60 as well as cutoff valve 5 being closed, cutoff valve 7 isopened by control section 30.

[0098] As a result, fuel retained in fuel feed line 11 is dischargedinto the atmosphere through fuel discharge line 9, and the pressurewithin fuel feed line 11 lowers to a value close to atmosphericpressure.

[0099] Next, nozzle 21 is removed from receptacle 71 and fuel fillingoperation is completed followed by waiting for an automobile to comewhen refueling is required.

[0100] In this standby state, the pressure within fuel distribution line2 and fuel feed line 11 is maintained at a value close to atmosphericpressure.

[0101] The changes in pressure within fuel feed line 11 during fillingoperation of fuel filling device 10 are shown in FIG. 3.

[0102] As shown in FIG. 3, the pressure within fuel feed line 11 duringstandby is pressure P0 close to atmospheric pressure.

[0103] When filling is started, pressure P0 rises to the pressure of theconnected storage tank, and as the storage tank is sequentially switchedto storage tanks at a higher pressure, continues to rise to the pressurecorresponding to the pressure of that storage tank, eventually rising tothe desired filling pressure PF.

[0104] Together with completion of filling, since fuel within fuel feedline 11 is discharged into the atmosphere through fuel discharge line 9,the pressure within fuel feed line 11 drops to pressure P0 nearatmospheric pressure followed by entering the standby state.

[0105] Subsequently, as standby and filling are repeated, the pressurewithin fuel feed line 11 repeatedly changes P0 (pressure during standby)to PF (pressure during filling) to P0 (pressure during standby) to PF(pressure during filling).

[0106] In fuel filling device 10 according to the present embodiment,since fuel discharge line 9 is provided that discharges fuel within fuelfeed line 11 to the outside, fuel within fuel feed line 11 and the likecan immediately be discharged from fuel discharge line 9 followingcompletion of filling, and fuel filling device 10 is able to wait in astandby state in which the pressure within fuel feed line 11 has beenlowered to nearly atmospheric pressure.

[0107] Consequently, the packings used for each of the compositeequipment that compose fuel filling device 10 (such as packings 18 athrough 18 m of emergency release pipe coupling 12) are prevented frombeing exposed to high-pressure fuel for long periods of time while inthis state, thereby making it possible to prevent fuel from permeatinginto the packings.

[0108] Accordingly, deterioration of the packings caused by permeationby penetration of fuel can be prevented, and accidents involving leakageof fuel and the like can be prevented.

[0109] In addition, operation such as connection and release of nozzle21 can also be facilitated since the pressure within nozzle 21 is at alow pressure while in this standby state.

[0110] In addition, as a result of providing check valve 8 in fueldischarge line 9, an inflow of air into fuel feed line 11 and the systemconnected thereto can be prevented even if the pressure followingcompletion of filling drops suddenly, and the inside of the system canalso be maintained at low pressure.

[0111] Consequently, the pressure change at completion of filling can bedecreased, the resulting effects on the packings can be suppressed, andpacking deterioration can be prevented.

[0112] In addition, as a result of installing check valve 8, the entryof atmospheric components into fuel tank T of automobile W can beprevented when fuel is filled into the next automobile W.

[0113] Moreover, since air remaining between filling port 22 of nozzle21 and a check valve 75 arranged in fuel tank T of automobile W is notallowed to enter fuel tank T during filling of fuel, entrance of air canbe reliably prevented by repeating pressurized filling and atmosphericdischarge several times on paths in which air is present prior tofilling fuel tank T.

[0114] The number of times of this operation should be determined eachtime according to the pressurized filling pressure and amount ofatmospheric components allowed by automobile W. In addition, thisoperation of repeating pressurized filling and atmospheric dischargeshould be made to be performed simultaneous to pressing the start button(not shown).

[0115] In addition, the coupling sections of equipment made of metalmaterials that compose fuel filling device 10, and particularly thosecoupling sections in which insulated sealing tape is interposed betweenconnecting members, are preferably grounded by coupling with a conductorwhile maintaining electrical conductivity.

[0116]FIG. 4 shows a coupling part 20 between fuel distribution line 2and fuel feed line 11. Coupling part 20 shown here is connected in astate in which connecting member 2 a on the side of fuel distributionline 2 and connecting member 11 a on the side of fuel feed line 11 arecoupled by screwing together with a sealing tape (not shown) in between.

[0117] Connecting member 2 a preferably employs a constitution in whichit is grounded through fuel supply adjusting section 1.

[0118] In this coupling part 20, one end and the other end of awire-shaped conducting member 23 composed of a metal or other conductorare attached to connecting member 2 a and connecting member 11 a, and asa result, connecting member 2 a and connecting member 11 a areelectrically conductive.

[0119] Since fuel feed line 11 is provided with a tubular resin orrubber body, and metal protective wire spiraled around its periphery, itis electrically conductive in the lengthwise direction. Furthermore,since rubber is more flexible than resin, the fuel feed line ispreferably made of rubber in consideration of ease of operation.

[0120] By coupling fuel distribution line 2 and fuel feed line 11 usingconducting member 23, static electricity generated by friction duringfuel flow and nozzle connection in parts such as fuel feed line 11 andnozzle 21 can be dissipated through connecting member 11 a, conductingmember 23, connecting member 2 a, and fuel supply adjusting section 1.

[0121] For example, in the case static electricity has been generated inautomobile W (for example, in the case static electricity has beengenerated when connecting nozzle 21 to receptacle 71 of automobile W),this static electricity can be dissipated through fuel feed line 11,connecting member 11 a, conductive member 23, connecting member 2 a, andfuel supply adjusting section 1.

[0122] Thus, fuel filling device 10 can be operated safely by preventingaccidents involving fires caused by static electricity.

[0123] Although the case of connecting two connecting members by meansof sealing tape is illustrated in FIG. 4, the present invention is notlimited to this, but rather the case in which two connecting members areconnected by means of an O-ring is similarly capable of preventingaccidents involving fire in advance by dissipating static electricity.

[0124] In fuel filling device 10, a fuel leakage detection device 31 ispreferably provided that detects fuel leakage within the system.

[0125] Fuel leakage detection device 31 detects the pressure of fueldistribution line 2 upstream from flow rate adjusting valve 4 withpressure switch 25, detects the pressure downstream from flow rateadjusting valve 4 with pressure switch 6, and transmits the detectionsignals from these switches to control section 30.

[0126] When the opening of flow rate adjusting valve 4 is made to beconstant (flow rate Q), the instantaneous flow rate of the fuel isdetermined by the pressure difference between the upstream side anddownstream side of flow rate adjusting valve 4.

[0127] In control section 30, by preliminarily creating a databasepertaining to the relationship between instantaneous flow rate andpressure difference, successively reading the pressure differencesduring filling as calculated from the detected values of pressure switch25 and pressure switch 6, and then integrating the instantaneous flowrate as calculated from this pressure difference and flow rate (Q), thetheoretical filling volume (F0) can be calculated and stored in memory.

[0128] On the other hand, in mass flow meter 3, filling volume (F) offuel actually supplied from fuel source 60 is measured, and this actualfilling volume (F) is transmitted to control section 30.

[0129] In control section 30, theoretical filling volume (F0) and actualfilling volume (F) are compared, their difference in the form of ΔF=F0−Fis calculated, and that difference is then displayed on display 32 asleakage volume (ΔF).

[0130] In fuel leakage detection device 31, fuel leakage is detected bycomparing theoretical filling volume (F0) and actual filling volume (F).Namely, the presence or absence of fuel leakage is judged according tothe size of difference ΔF between theoretical filling volume (F0) andactual filling volume (F). For example, fuel leakage can be judged tohave occurred when difference ΔF has exceeded a specified value α.

[0131] Thus, fuel leakage can be detected both accurately and rapidly.

[0132] In addition, in comparison with conventional detection methods inwhich fuel leakage is detected by fuel sensors provided at locationssusceptible to the occurrence of fuel leakage, since the detectionmethod using detection device 31 indicated here detects fuel leakage bycomparing theoretical filling volume (F0) and actual filling volume (F),fuel leakage can be detected immediately regardless of the locationwhere fuel leakage occurs.

[0133] In addition, by making it such that an alarm sounds whendifference ΔF has exceeded (or fallen below) a specified value α,leakage of fuel can be detected immediately.

[0134] Moreover, safety can be enhanced by making it such that cutoffvalve 5 is activated to interrupt the supply of fuel at this time.

[0135] Furthermore, stricter monitoring can be performed by measuringthe gas temperature of this data and then correcting the temperature.

[0136] This leakage detection method is not limited to fuel fillingdevice 10 for filling fuel into automobile W, but rather can also beapplied to all other types of fuel supply, and is capable of ensuring astable supply of fuel.

EXAMPLES

[0137] A packing durability test was conducted in the manner describedbelow. The specimens used in this testing are indicated below.

[0138] (1) Rubber Materials

[0139] (a) Materials: acrylonitrile butadiene rubber, hydrogenatedacrylonitrile butadiene rubber, ethylene propylene rubber, fluorinerubber, chlorinated butyl

[0140] (b) Shape: dumbbell (JIS K 6251 No. 3) and O-ring (AS568A-116)

[0141] (2) Resin Materials

[0142] (a) Materials: polyoxymethylene (polyacetal), nylon (polyamide),polyphenylenesulfide

[0143] (b) Shape: dumbbell (Type ASTM1, thickness: 3 mm)

[0144] (3) Resin (Coated) Materials

[0145] (a) Materials: main body; silicone resin, fluororesin, coating;Teflon (registered trademark)

[0146] (b) Shape: O-ring (AS568A-116)

[0147] The test method is described below.

[0148] After placing the specimen in a container, filling the containerwith hydrogen gas, and allowing to stand for 1 week at a pressure of 35MPa, the hydrogen gas was evacuated from the container. When evacuatingthe hydrogen gas, evacuation was completed in about 30 minutes to thatpressure inside the container decreased rapidly.

[0149] The dumbbell-shaped specimens were evaluated for appearance,tensile strength, elongation, thickness of parallel parts, width ofparallel parts and hardness. O-ring-shaped specimens were evaluated forappearance, thickness and inner diameter.

[0150] Testing of tensile strength and elongation was performed incompliance with JIS K 6258.

[0151] In this test, in the case of the dumbbell-shaped specimens madeof rubber materials, the distance between the bench marks was set at 20mm, and the pulling speed was set at 500 mm/min. In the case of thedumbbell-shaped specimens made of resin materials, the distance betweenthe bench marks was set at 50 mm, and the pulling speed was 10 mm/min.

[0152] Thickness was measured using a dial gauge. Width and innerdiameter were measured using a profile projector. Hardness was measuredusing a Wallace hardness gauge.

[0153] In each of the above evaluation tests, three specimens were usedin testing to represent a single sample. In addition, the amount ofchange and change ratio before and after testing were calculated foreach item from the measured values before testing and the measuredvalues after testing. The test results are shown in Tables 1 through 5.TABLE 1 Tensile Strength Before After Change Elongation test test ratioBefore After Change Specimen Material Type Shape Appearance (MPa) (MPa)(%) test (%) test (%) ratio (%) 1 NBR Rubber Dumbbell — 20.4 19.6 −4 365349 −4 2 20.7 18.8 −9 378 321 −15 3 20.1 19.6 −2 358 355 −1 4 NBR RubberDumbbell — 17.5 18.1 4 168 170 5 21.7 16.2 −25 213 152 −29 6 18.8 18.5−1 168 178 6 7 HNBR Rubber Dumbbell Matte 20.3 17.4 −14 166 149 −10 819.5 18.8 −4 154 147 −5 9 19.9 19.9 0 150 156 4 10 HNBR Rubber DumbbellCoarse, 22.1 12.5 −43 143 82 −43 11 highly 21.3 18.2 −15 140 115 −18 12foamed 22.8 20.6 −10 149 138 −7 13 EPR Rubber Dumbbell — 19.1 18.5 −3238 231 −3 14 17.4 17.9 3 228 223 −2 15 19.6 17.3 −12 238 217 −9 16 EPRRubber Dumbbell Partly 15.8 14.8 −6 143 135 −6 17 foamed 15.6 14.1 −10153 130 −15 18 15.5 14.9 −4 143 135 −6 19 FKM Rubber Dumbbell — 16.012.5 −22 320 220 −31 20 13.8 15.0 8 284 498 76 21 14.8 15.6 5 289 316 922 FKM Rubber Dumbbell Partly 15.1 14.7 −2 262 268 2 23 matte 15.2 13.8−9 280 315 13 24 15.0 14.8 −2 26 266 0 25 FKM Rubber Dumbbell — 17.514.9 −15 212 179 −16 26 16.4 14.9 −9 183 170 −7 27 16.2 14.9 −8 199 177−11 28 BC Rubber Dumbbell — 16.3 11.9 −27 232 222 −4 29 15.8 13.2 −16227 180 −21 30 16.3 11.1 −32 230 168 −27

[0154] TABLE 2 Thickness Width Hardness Before After Change Before AfterChange Before After Change test test ratio test test ratio test testratio Specimen Material Type Shape (mm) (mm) (%) (mm) (mm) (%) (−) (−)(−) 1 NBR Rubber Dumbbell 2.205 2.253 2 5.070 5.104 1 68.0 69.0 1 22.250 2.303 2 5.015 5.020 0 69.0 70.0 1 3 2.172 2.213 2 5.060 5.065 068.5 69.0 0.5 4 NBR Rubber Dumbbell 2.170 2.307 6 5.054 5.196 3 84.086.0 2 5 2.200 2.333 6 5.052 5.190 3 83.5 84.0 0.5 6 2.190 2.323 6 5.0545.208 3 84.0 86.0 2 7 HNBR Rubber Dumbbell 2.530 2.480 −2 5.043 5.046 073.0 74.0 1 8 2.510 2.517 0 5.055 5.006 −1 73.0 75.0 2 9 2.470 2.543 35.051 5.121 1 73.0 74.0 1 10 HNBR Rubber Dumbbell 2.230 2.217 −1 5.0425.068 1 83.5 87.0 3.5 11 2.180 2.180 0 5.047 4.999 −1 84.0 86.0 2 122.350 2.345 0 5.044 5.104 1 85.0 87.0 2 13 EPR Rubber Dumbbell 2.3402.333 0 5.054 5.074 0 72.0 73.0 1 14 2.213 2.210 0 5.051 5.119 1 71.074.0 3 15 2.345 2.347 0 5.059 5.087 1 70.5 74.0 3.5 16 EPR RubberDumbbell 2.062 2.063 0 5.039 5.022 0 72.0 87.0 15 17 2.072 2.070 0 5.0375.044 0 74.5 86.0 11.5 18 2.100 2.103 0 5.045 5.085 1 78.0 86.0 8 19 FKMRubber Dumbbell 2.105 2.170 3 5.051 5.119 1 66.0 67.0 1 20 2.062 2.130 35.066 5.137 1 66.0 68.0 2 21 2.060 2.137 4 5.073 5.182 2 66.0 68.0 2 22FKM Rubber Dumbbell 2.075 2.140 3 5.067 5.142 1 84.0 86.0 2 23 2.1602.227 3 5.061 5.151 2 84.5 86.0 1.5 24 2.100 2.170 3 5.065 5.142 2 84.584.0 −0.5 25 FKM Rubber Dumbbell 2.410 2.487 3 5.135 5.195 1 79.5 81.01.5 26 2.390 2.493 4 5.081 5.194 2 81.0 82.0 1 27 2.420 2.497 3 5.1395.116 0 81.0 83.0 2 28 BC Rubber Dumbbell 2.350 2.643 12 5.173 5.650 966.5 62.0 −4.5 29 1.880 2.087 11 5.189 5.507 6 66.0 63.0 −3 30 2.0402.287 12 5.166 5.756 11 66.0 62.0 −4

[0155] TABLE 3 Thickness Inner Diameter Before After Change Before AfterChange test test ratio test test ratio Specimen Material Type ShapeAppearance (mm) (mm) (%) (mm) (mm) (%) 31 NBR Rubber O-ring — 2.6052.600 −0.19 18.799 18.791 −0.05 32 2.613 2.610 −0.11 18.753 18.747 −0.0333 2.602 2.595 −0.25 18.730 18.698 −0.17 34 NBR Rubber O-ring — 2.6652.695 1.13 18.750 18.819 0.37 35 2.647 2.675 1.06 18.780 18.835 0.29 362.655 2.685 1.15 18.727 18.784 0.31 37 HNBR Rubber O-ring — 2.640 2.635−0.19 18.703 18.659 −0.24 38 2.628 2.620 −0.30 18.697 18.649 −0.25 392.617 2.615 −0.08 18.733 18.729 −0.02 40 HNBR Rubber O-ring — 2.6262.615 −0.42 18.738 18.706 −0.17 41 2.631 2.635 0.15 18.725 18.694 −0.1742 2.629 2.640 0.42 18.695 18.689 −0.03 43 EPR Rubber O-ring — 2.6292.630 0.04 18.711 18.692 −0.10 44 2.634 2.635 0.04 18.763 18.760 −0.0245 2.644 2.645 0.06 18.639 18.626 −0.07 46 EPR Rubber O-ring — 2.6422.635 −0.25 18.718 18.707 −0.06 47 2.657 2.645 −0.43 18.672 18.650 −0.1248 2.626 2.625 −0.02 18.712 18.865 0.81

[0156] TABLE 4 Thickness Inner Diameter Before After Change Before AfterChange test test ratio test test ratio Specimen Material Type ShapeAppearance (mm) (mm) (%) (mm) (mm) (%) 49 FKM Rubber O-ring — 2.6052.595 −0.38 18.533 18.505 −0.15 50 2.616 2.610 −0.23 18.465 18.455 −0.0651 2.618 2.615 −0.10 18.513 18.479 −0.18 52 FKM Rubber O-ring — 2.6432.650 0.28 18.614 18.696 0.44 53 2.633 2.660 1.04 18.629 18.677 0.26 542.634 2.645 0.42 18.581 18.633 0.28 55 FKM Rubber O-ring — 2.542 2.5450.14 18.467 18.524 0.31 56 2.542 2.555 0.51 18.503 18.556 0.29 57 2.5412.560 0.77 18.470 18.481 0.06 58 BC Rubber O-ring Coarse, 2.573 2.6503.01 18.696 19.157 2.47 59 highly 2.582 2.650 2.63 18.700 19.169 2.51 60foamed 2.574 2.635 2.39 18.664 19.044 2.03 61 *1 Coated O-ring Broken3.645 3.640 −0.12 — — — 62 3.614 3.580 −0.93 — — — 63 3.573 3.565 −0.21— — — 64 *2 Coated O-ring Broken 3.619 3.665 1.27 — — — 65 3.591 3.6000.25 — — — 66 3.697 3.750 1.43 — — — 67 3.654 3.720 1.81 — — —

[0157] TABLE 5 Tensile Strength Elongation Thickness Width Before AfterChange Before After Change Before After Change Before After Change Spec-Mate- Appear- test test ratio test test ratio test test ratio test testratio imen rial Type Shape ance (MPa) (MPa) (%) (%) (%) (%) (mm) (mm)(%) (mm) (mm) (%) 68 POM Resin Dumb- — 59.5 56.8 −5 42 94 124 3.1653.343 6 12.732 12.697 0 69 bell 59.5 56.9 −5 61 110 81 3.165 3.177 012.727 12.771 0 70 60.2 57.3 −5 61 94 55 3.165 3.240 2 12.732 12.724 071 PA Resin Dumb — 103.2 88.0 −15 — — — 4.005 3.973 −1 9.929 9.881 0 72bell 96.1 88.2 −8 — — — 4.000 3.980 0 9.951 9.942 0 73 97.6 85.6 −12 — —— 4.005 3.977 −1 9.942 9.919 0 74 PA Resin Dumb- — 210.7 212.4 1 — — —3.915 4.023 3 10.013 9.961 −1 75 bell 220.3 190.1 −14 — — — 3.907 4.0133 9.980 9.978 0 76 227.0 203.2 −10 — — — 3.915 4.027 3 9.994 9.985 0 77PPS Resin Dumb- Partly 77.5 75.3 −3 −4 7 −292 3.108 3.140 1 12.62512.680 0 78 bell 79.4 76.3 −4 3 7 181 3.110 3.127 1 12.552 12.653 1 7978.6 73.3 −7 1 7 822 3.100 3.157 2 12.620 12.590 0

[0158] Each specimen was evaluated according to the following standardsbased on the test shown in Tables 1 through 5.

[0159] (a) Appearance: Absence of abnormalities such as foaming andbreaking

[0160] (b) Tensile strength: Absence of significant decrease withrespect to product specifications

[0161] (c) Elongation: Absence of significant decrease with respect toproduct specifications

[0162] (d) Thickness: Absence of significant change with respect todimensions before testing

[0163] (e) Width or inner diameter: Absence of significant change withrespect to dimensions before testing

[0164] (f) Hardness: Absence of significant hardening or softening withrespect to product specifications

[0165] The following conclusions can be drawn from the above testresults.

[0166] (1) Acrylonitrile butadiene rubber, hydrogenated acrylonitrilebutadiene rubber, ethylene propylene rubber, fluorine rubber,polyoxymethylene (polyacetal), and nylon (polyamide) exhibit smallchanges in mechanical properties (tensile strength, elongation andhardness) and dimensions, and their change in appearance is alsocomparatively small.

[0167] (2) Acrylonitrile butadiene rubber, ethylene propylene rubber,and nylon (polyamide) in particular exhibit small changes in mechanicalproperties and dimensions, and their change in appearance is also small.

[0168] (3) In the case of using acrylonitrile butadiene rubber,specimens 1 through 3, which had a hardness of 75 or less beforetesting, exhibited small changes in mechanical properties as comparedwith specimens 4 through 6, which had a hardness greater than 75.

[0169] (4) In the case of using ethylene propylene rubber, specimens 13through 15, which had a hardness of 72 or less before testing, exhibitedsmall changes in both mechanical properties and appearance as comparedwith specimens having a hardness greater than 72.

[0170] (5) Breakage of the coating occurred in the case of using resin(coated) materials.

[0171] (6) Chlorinated butyl exhibited significant decreases in tensilestrength, elongation and thickness. In addition, foaming was observed inO-ring-shaped specimens.

[0172] (7) Polyphenylenesulfide exhibited a large decrease in tensilestrength.

[0173] Furthermore, these conclusions were not obtained from a specifictest, but rather are based on judgments obtained based on acomprehensive evaluation of each of the above test results. In addition,the elongation test of polyamide resin was omitted from Table 5 sincethe reliability of the measured values was low.

What is claimed is:
 1. A fuel filling device which fills hydrogen gas orcompressed natural gas a fuel tank of a vehicle as fuel, comprising: afuel supply adjusting section which adjusts an amount of fuel supplied;a fuel feed line which feeds fuel from the fuel supply adjusting sectionto the vehicle; a nozzle removably coupled to the vehicle which suppliesfuel from the fuel feed line to the vehicle; and a discharge devicewhich discharges fuel within the fuel feed line to outside.
 2. A fuelfilling device according to claim 1, wherein the fuel supply adjustingsection is provided with a fuel distribution line which guides the fuelto the fuel feed line, and the discharge device is connected to the fueldistribution line.
 3. A fuel filling device according to claim 1,wherein a packing used for the fuel supply adjusting section, fuel feedline, or nozzle is composed of one or two or more selected from thegroup consisting of acrylonitrile butadiene rubber, hydrogenatedacrylonitrile butadiene rubber, ethylene propylene rubber, fluorinerubber, polyacetal, and polyamide.
 4. A fuel filling device according toclaim 1, wherein a packing used for the fuel supply adjusting section,fuel feed line, or nozzle is composed of one or two or more selectedfrom the group consisting of acrylonitrile butadiene rubber, ethylenepropylene rubber, and polyamide.
 5. A fuel filling device according toclaim 1, wherein the fuel feed line and fuel supply adjusting sectionare coupled with an electrically conductive member, and the fuel supplyadjusting section is grounded.
 6. A fuel filling device according toclaim 1, wherein a flow meter which measures a flow rate of the fuel anda flow rate adjusting valve which adjusts a flow rate of the fuel areprovided in the fuel supply adjusting section, to enable a theoreticalfilling volume, which is calculated based on the flow rate of the fuelcalculated from an opening of the flow rate adjusting valve and apressure difference between an upstream pressure and a downstreampressure of the flow rate adjusting valve, to be compared with an actualfilling volume detected with the flow meter.
 7. A method of detectingfuel leakage of a fuel filling device which fills hydrogen gas orcompressed natural gas into a fuel tank of a vehicle as fuel comprising:a fuel filling device being provided with a fuel supply adjustingsection that adjusts the amount of fuel supplied, and a fuel supplyadjusting section being provided with a flow meter which measures a flowrate of the fuel, and a flow rate adjusting valve which adjusts a flowrate of the fuel; wherein fuel leakage is detected by comparing atheoretical filling volume calculated based on an opening of the flowrate adjusting valve and a pressure difference between an upstreampressure and a downstream pressure of the flow rate adjusting valve, andan actual filling volume detected with the flow meter.